Microcystic pseudoglandular plexiform cutaneous neurofibroma

Glandular structures are well documented to appear in peripheral nerve sheath tumors. These epithelial elements are usually present in malignant peripheral nerve sheath tumors although a few cases of glandular benign peripheral nerve sheath tumors have also been described, most of them being schwannomas. A neurofibroma with glands is considered to be a rare type of divergent differentiation, but a neurofibroma containing gland‐like or pseudoglandular structures have not, to our knowledge, been described. We report a 33‐year‐old patient with a well‐demarcated dermal neoplasm, composed of neoplastic Schwann cells, perineurial‐like cells and fibroblasts in a matrix with collagen fibers and myxoid areas. A part of the tumor consisted of microcystic gland‐like spaces lined by flat cells. These cells were either S100 positive or negative, with no epithelial membrane antigen, cytokeratin or CD31 immunostaining. Recognition of the presence of pseudoglandular elements in neurofibromas is important to distinguish them from other tumoral lesions, some of them with malignant potential.     

Pigmented neurofibroma

A 24-year-old male patient suffering from a large-coconut-sized neurofibroma is described. In the tumor, sharply demarcated areas of melanin containing cells were seen. These cells were identified as melanin producers by the premelanosomes seen by electron microscope. Although the coexistence of neurofibroma with another melanin-producing tumor, such as cellular blue nevus, could not be ruled out, this tumor shows the close relationship between tumors of the peripheral nervous system and melanocytic malformations or pigmented nevi. These observations are relevant to the controversy over the histiogenesis of these pigmented lesions and support Masson's view that nerve sheath cells are capable of melanogenesis.     

Four Japanese cases of dendritic cell neurofibroma with pseudorosettes

Dendritic cell neurofibroma with pseudorosettes (DCNWPR) is a rare peripheral nerve sheath tumor (PNST). To our knowledge, the only reported case of DCNWPR in Japan was documented by our team. We experienced three additional cases of DCNWPR in our institute since 2007, and report the clinical and histological features of DCNWPR of these Japanese cases. All four patients were adult women, with ages ranging 48–77 years (mean, 63.8). All patients presented with small solitary lesions that were clinically diagnosed as fibroma, melanocytic nevus or mixed tumor of the skin. Three cases were located on the back, and one on the cheek. Histopathologically, well‐circumscribed nodules were present in the dermis, and composed of small lymphocyte‐like cells with dark nuclei (type I cells) and larger cells with pale vesicular nuclei and abundant eosinophilic cytoplasm (type II cells). Small type I cells were grouped concentrically around the larger type II cells, thereby forming pseudorosettes. Immunohistochemical studies using antibodies against CD57 and S100 protein revealed that type II cells contained a copious cytoplasm endowed with a network of slender dendritic extensions. CD57 should be a useful marker for identifying type II cells because it allows these cells to be stained exclusively. We should recognize DCNWPR with its characteristic histological features such as pseudorosettes and presence of dendritic type II cells as a variant of PNST.     

Malignant peripheral nerve sheath tumor arising from solitary neurofibroma

Malignant peripheral nerve sheath tumors (MPNSTs) are rare sarcomas that are strongly associated with neurofibromatosis type I (NF-1). We describe a 71-year-old woman with no stigmata of neurofibromatosis, who presented with recurrent subcutaneous tumor on her left upper back. She received two excisional biopsies on the back of her trunk at our hospital and both pathology reports revealed neurofibromas. Three years after the last skin biopsy, a rapidly growing subcutaneous tumor emerged at the same site. This tumor was totally resected and the histopathology showed an ill-defined tumor in the dermis and subcutaneous tissue. The tumor was composed of spindle cells in a myxoid stroma with a transition from the area of typical neurofibroma to the hypercellular area. The hypercellular area consisted of atypical, hyperchromatic spindled cells with frequent mitotic figures. She was therefore diagnosed with MPNST.     

Superficial malignant peripheral nerve sheath tumor arising from diffuse neurofibroma in a neurofibromatosis type 1 patient

Malignant peripheral nerve sheath tumors (MPNST) are regarded as sarcomas that arise from peripheral nerves or that display differentiation along the lines of the various elements of the nerve sheath. These tumors occur in deep soft tissues, but superficial primary MPNST with a cutaneous or subcutaneous origin have rarely been reported. A 70‐year‐old woman presented with a 3–4‐year history of a slowly enlarging soft nodule on the left side of her neck. The histopathological diagnosis of the nodule was low‐grade MPNST arising from diffuse neurofibroma. There was increased cellularity, but no necrosis or mitotic activity. These histopathological findings pose difficulties in differential diagnosis from a neurofibroma with atypical histological features. We report a rare case of superficial MPNST arising from diffuse neurofibroma associated with underlying occipital bone dysplasia in a neurofibromatosis type 1 patient.     

头皮局限性神经纤维瘤伴脱发一例

患者,男,22岁。脱发1年余,头皮棕褐色肿物6个月。病理可见毛囊微小化,真皮下部大量细长梭形瘤细胞,波浪状排列。S-100多克隆(+),SOX-10(+),MelanA(+),Vimentin-10(+)。诊断为头皮局限性神经纤维瘤。后行手术治疗,随访中。     

Hemorrhage into a plexiform neurofibroma induced by trauma: a rare complication of von Recklinghausen's disease

A case of hemorrhage into a plexiform neurofibroma of a 53-year-old woman is described. Immediately after trauma to the plexiform neurofibroma on her scalp, she noticed severe headaches and sudden enlargement of the tumor. The tumor continued to enlarge slowly. Her headaches also continued until tumor excision. The specimen taken during surgery surrounded a round cavity about 7 cm in diameter containing coagulated blood. Numerous, old, perivascular hemorrhages around many dilated vessels with extremely thin walls were revealed by histological examination.     

A Case of Malignant Peripheral Sheath Tumor Arising from Neurofibromatosis Type 1

Malignant peripheral nerve sheath tumor (MPNST) is a term encompassing tumors previously diagnosed as malignant schwannoma, malignant neurilemmoma, neurogenic sarcoma, and neurofibrosarcoma The occurrence rate of MPNST in neurofibromatosis type 1 patients is known to be about 4.6%. Tumors occurring in this particular group have a worse prognosis in that they occur at an earlier age, are more centrally located, tend to be of a larger size and show more metastases and recurrences. We present a typical case of MPNST in a 36-year-old man with NF type 1, which occurred on the left buttock. A PET-CT showed findings of possible inguinal lymph node metastasis and a lymph node biopsy confirmed the diagnosis. The patient was treated with wide surgical resection and is undergoing adjuvant radiation therapy.     

Case of pigmented neurofibroma with hypertrichosis with no association to neurofibromatosis

Pigmented neurofibroma (PNF) is a rare cutaneous tumor that has been observed in patients with or without neurofibromatosis (NF). This tumor is histologically characterized by the coexistence of scattered melanin-laden cells and benign spindle cells with neural differentiations. Hypertrichosis is the excessive growth of hair on non-androgen-dependent areas of the body. It has been reported that hypertrichosis may sometimes overlie a neurofibroma. We highlight a case of PNF with hypertrichosis on a 17-year-old woman with no associated NF. We also discuss the possible underlying pathogenic mechanism of a localized hypertrichosis in PNF patients.     

A rare variant of erythema nodosum leprosum: a case report

We report a patient with lepromatous leprosy who developed a rare variant of type-2 lepra reaction, characterized by pustular lesions, on switching from WHO multi drug therapy (MDT) to ofloxacin-aided MDT.     

Solitary cellular schwannoma (neurilemmoma) showing malignant changes: evaluation through magnetic resonance imaging (M.R.I.), surgical intervention, and histopathology

Schwannoma (neurilemmoma) are common benign tumors arising from the peripheral nerve sheath. Malignant transformation is uncommon. A unique case showing such a transformation is reported highlighting the roles of magnetic resonance imaging, surgical intervention, and histopathology. The case was thoroughly investigated by learning the details of the sequence of events leading to the current status. The evaluation was made through magnetic resonance imaging. In addition, computed tomography and conventional radiography were used to locate any foci of calcification. Subsequently, the tumor's gross and microscopic morphology was defined by surgical intervention and histopathology. Malignant schwannoma of the left leg occupying the entire calf is extremely uncommon. Only ten cases have been reported thus far, including the current one from the Indian subcontinent. Malignant transformation in a schwannoma differs significantly from malignant nerve sheath tumors (erroneously called malignant schwannomas). An endeavour has been made to differentiate malignant transformation in schwannoma from other malignant peripheral nerve sheath tumors. An innovation in this direction is magnetic resonance imaging. This investigate procedure is imperative in such situations, along with surgery and histopathology, which may also help in classifying the condition.     

Distribution of diffuse plexiform neurofibroma on the body surface in patients with neurofibromatosis 1

Neurofibromatosis 1 (NF1) is a genetic disease characterized by cutaneous, neurological and osseous abnormalities. Approximately 20% of patients develop plexiform neurofibroma (PN), resulting in impaired quality of life. To evaluate distribution of diffuse PN on the body surface, a retrospective study was conducted for 354 patients with NF1 from 2007 to 2018 in Japan. We investigated a total of 40 patients with clinically apparent superficial diffuse PN. In the cases evaluated, 57.4% of the diffuse PN were located on the trunk, 19.2% the head and neck, 12.8% the lower limbs and 10.6% the upper limbs. Remarkably, 75.0% of the diffuse PN were located on the dorsal side. The frequency was significantly higher on the trunk than on the head and neck (P = 0.026). Our findings provide useful information for giving attention to the high possibility of diffuse PN on the dorsal side before progression in childhood and for future treatment in NF1.     

A Case of Pigmented Dermatofibrosarcoma Protuberans (Bednar Tumor)

The present paper reports a 67-year-old male with pigmented dermatofibrosarcoma protuberans (Bednar tumor) on his right shoulder. The lesion had recurred twice. Clinically, the lesion was a reddish-brown, exophytic, multilobular, firm nodule with an irregular surface, which measured 6.4 times 4.2 cm. Histologically, the proliferated fibroblasts showed a cartwheel pattern and stained positively with CD34, similar to those of a common dermatofibrosarcoma protuberance. However, many melanin-bearing cells that were positive for the S-100 protein were found intermingled among the tumor cells. Based on these findings, we concluded that the clinical manifestations, level of malignancy, and cytological features, as well as the exception of melanin-bearing dendritic cells associated with pigmented dermatofibrosarcoma protuberans, suggest a common dermatofibrosarcoma protuberans. This supports the hypothesis that pigmented dermatofibrosarcoma protuberans is a pigmented variant of dermatofibrosarcoma protuberans. Thus, this type of tumor is not benign, but is an intermediate malignant tumor.     

A Case of Isolated Plexiform Neurofibroma in a Patient with Myasthenia Gravis

We report a case of an isolated plexiform neurofibroma occurring in a patient with myasthenia gravis. A 48-year-old man presented with asymptomatic skin-colored nodules on the tip of his 4th finger. Microscopically, a plexiform neurofibroma was identified located in the dermis that appeared to originate from small superficial nerves. He had a 20-year history of treated myasthenia gravis; otherwise, his personal and family histories were unremarkable. Given that myasthenia gravis is a disorder of the peripheral nerves, plexiform neurofibromas could be associated with myasthenia gravis. However, the development of an isolated plexiform neurofibroma in a case of myasthenia gravis has not yet been reported. The occurrence of a neurofibromas in a patient with myasthenia gravis suggests a link in the pathogenesis of these two diseases.     

An incidental finding of an asymptomatic intraneural glomus tumor: A case report and review of the literature

Glomus tumors are rare, soft‐tissue neoplasms arising from the thermoregulatory neuromyoarterial glomus bodies. They are commonly observed in the extremities and typically present with symptoms of cold hypersensitivity, pain and localized tenderness. Intraneural glomus tumors (INGTs) are even rarer. Here we review the literature on INGT and present an unusual case of an asymptomatic INGT, found incidentally within the excision specimen of a spiradenocarcinoma that arose near the natal cleft. Interestingly, this had not been identified on magnetic resonance imaging (MRI) used to investigate the spiradenocarcinoma. Although glomus tumors are usually considered benign, malignant transformation has been reported, highlighting the need for reporting pathologists and treating clinicians to be aware of this entity.     

Desmoplastic melanoma: a rare variant with challenging diagnosis - case report

Desmoplastic melanoma, a distinct and uncommon variant, is characterized as an invasive lesion with proliferation of fusiform melanocytes in the dermis and subcutaneous tissue, associated with varying patterns of desmoplasia. Neurotropism and neural differentiation may occur. The clinical presentation is variable and nonspecific, easily confused with other fibrous neoplasms. The disease is locally aggressive and shows lower metastasis rates than other types of melanoma. Histopathology may be insufficient, requiring positive immunohistochemistry for S-100 protein and other antigens of melanocytic differentiation. Because desmoplastic melanoma represents a true clinical, dermoscopic, and histopathological diagnostic challenge, a case of invasive desmoplastic melanoma is reported, affecting a photoexposed area in an elderly woman after histological revisions and an initial diagnosis of fibroma.